package string;

public class StringBuilderDemo {
    public static void main(String[] args) {
        String str="好好学习JAVA";
        StringBuilder builder=new StringBuilder(str);//

        builder.append("，为了找个好工作 ");//在末尾追加
        System.out.println(builder);

        builder.replace(9,16,"就是为了改变世界");//替换 含头不含尾
        System.out.println(builder);

        builder.delete(0,8);
        System.out.println(builder); //删除 含头不含尾

        builder.insert(0,"活着");//插入
        System.out.println(builder);












        /*
        StringBuilder builder1 = new StringBuilder();
        StringBuilder builder2 = new StringBuilder("abc");
        String str="abc";
        StringBuilder builder3=new StringBuilder("str");
        String str2=builder3.toString();

        */

    }
}
